In 1924, he was a member of the organizing committee for the founding, with Leonard Bloomfield and George M. Bolling, of the Linguistic Society of America (LSA).
Besides research on Native American languages and field work on the Modern American English dialects, he is the father of the Indo-Hittite hypothesis, first formulated in 1926, based on his seminal work establishing the Indo-European character of Hittite (and the related Anatolian languages), with Hittite exhibiting more archaic traits than the normally reconstructed forms for Proto-Indo-European.
He authored the first scientifically acceptable Hittite grammar with a chrestomathy and a glossary, formulated the so-called Sturtevant's law (the doubling of consonants representing Proto-Indo-European voiceless stops) and laid the foundations to what later became the Goetze–Wittmann law (the spirantization of palatal stops before u as the focal origin of the centum-satem isogloss).
The 1951 revised edition of his grammar (co-authored with E. Adelaide Hahn) is still useful today, although it was superseded in 2008 by Harry A. Hoffner and Craig Melchert's Grammar of the Hittite Language, for which a second edition was published in 2024.
His son, Julian M. Sturtevant, was a chemist and molecular biophysicist at Yale University.